How Doppler radar will change weather predictions in India

By 2025, the entire country will be covered by Doppler Weather Radar which means getting accurate weather forecasts and timely weather advisories.

To predict extreme weather conditions more accurately and to provide more precise farm-related advisories, the Indian government has chalked out a plan to cover the entire country under the very sophisticated Doppler Weather Radars by 2025. According to government reports, while there has been a 40 percent increase in the efficiency of weather prediction by Indian Meteorological Department (IMD) in the last 9 years, the deployment of an additional 25 sophisticated radar networks will change the entire scenario for the better.

The ambitious plan, along with a slew of other measures to enhance the country's weather prediction scenario, was announced by Union Minister of Earth Sciences Dr. Jitendra Singh and IMD chief Mrutyunjay Mohapatra during an event earlier this week to celebrate the 148th foundation day of the department.

So, what is this sophisticated Doppler Weather Radar (DWR) that once implemented will make sure all the weather predictions in the country are accurate and timely? Here is a simplified explanation of this sophisticated technology and how it will change the face of weather predictions in the country.

How do the radars work?

For many years, radars have been used to provide information about the intensity and extent of rain and other forms of precipitation.

The basics of radars is that a beam of energy, which are radio waves, is emitted from an antenna. When these waves strike any obstruction in the atmosphere, they scatter and deflect in different directions. Some of this energy also gets reflected back directly to the radar.

The larger the object, the greater the amount of energy that is returned. So when there are raindrops in the atmosphere, the energy reflects and radar helps humans know about rain. Also, how far the obstruction is from the radar can also be calculated based on the time the beams of energy return to the radar. The closer the raindrops, the faster the reflection. So these two factors help predict the location and intensity of rainfall in different places.

DWR: Why is it different?

Doppler Weather Radar works on the principle of Doppler's effect. Doppler effect is observed whenever the source of waves is moving with respect to an observer. For example, an ambulance crossing you with its siren blaring is a common physical demonstration of the Doppler Effect. As the pitch of the siren drops, one knows that the ambulance is going away.

Using the Doppler effect, the DWR captures even the smallest visible size, which we can call microscopic waves. When these waves collide with an object and return, this radar can easily detect their direction. Along with this, it can detect microscopic water droplets floating in the air and track their direction. Doppler radar updates the size of the droplets, their speed, and related information every minute.

Based on this information, it is not difficult to find out how much rain or storm will occur in any area. This can make a huge difference in the accuracy of the IMD's prediction, according to a report.

Designed to improve the accuracy of weather forecasting and monitoring, DWRs are equipped with instruments to measure rainfall intensity, wind gradient and speed. It informs about the direction of the dust storm as well. With its help, the department would be able to predict and accurately record the changes in the 400-km area around it. With this radar, no weather forecast would fail nor would any weather change go unnoticed.

In 2022 alone, 1285 people lost their lives due to lightning strikes, while 835 people lost their lives due to floods and heavy rains, according to a Times of India report. Doppler Weather Radar will help in observing extent and intensity of rainfalls and cloud formations, and monitoring thunderstorms and lightning in real-time. It can avert many disasters in states that are vulnerable to thunderstorms, lightning and heavy rains.

From 13 to 37 DWRs in 8 years

Dr. Singh said that the DWR network in the country has already increased from 13 to 37 in the last eight years and will add 25 more in the next 3-5 years for universal coverage of the country. On Sunday, four DWRs were inaugurated in the western Himalayan region - Banipal Top in Jammu and Kashmir, Jot and Murari Devi in Himachal Pradesh and Surkanda Devi in Uttarakhand.

The X-Band DWR installed in the Valley will be extremely helpful in assessing weather conditions during the Amarnath Yatra. Eleven of the 25 radars have been planned to be set up in the plains while eight in the North East, and six in urban areas.